A great effort has been made to develop technologies for cast molding of hydrogel contact lenses with high precision, fidelity and reproducibility and at low cost. One of such manufacturing technologies is the so-called Lightstream Technology™ (Alcon) involving reusable molds and curing a lens-forming composition under a spatial limitation of actinic radiation (U.S. Pat. Nos. 5,508,317, 5,583,163, 5,789,464, 5,849,810 and 8,163,206). The Lightstream Technology™ for making contact lenses have several advantages. For example, reusable quartz/glass molds or/and reusable plastic molds, not disposable plastic molds, can be used, because, following the production of a lens, these molds can be cleaned rapidly and effectively of the uncrosslinked monomer or prepolymer and other residues, using a suitable solvent and can be blown dried with air. Disposable plastic molds inherently have variations in the dimensions, because, during injection-molding of plastic molds, fluctuations in the dimensions of molds can occur as a result of fluctuations in the production process (temperatures, pressures, material properties), and also because the resultant molds may undergo non-uniformly shrinking after the injection molding. These dimensional changes in the mold may lead to fluctuations in the parameters of contact lenses to be produced (peak refractive index, diameter, basic curve, central thickness etc.) and to a low fidelity in duplicating complex lens design. By using reusable molds which are produced in high precision, one can eliminate dimensional variations inherently presented in disposable molds and thereby variation in contact lenses produced therefrom. Lenses produced according to Lightstream Technology™ can have high consistency and high fidelity to the original legs design.
However, the conventional re-usable contact lens mold consists of a quartz convex base curve and a glass concave front curve. The base curve mold is made of individually ground and polished quartz, while the front curve mold is made of high precision pressed and polished glass. The fabrication time for new design quartz base curve molds and glass front curve molds is several months. Such long lead-times result in lengthy development cycles and long lead times for prototyping molds.
Therefore, there is still a need for new reusable molds that can be designed and fabricated in a relatively shorter time.